ABSTRACT
The vast majority of commercial polymeric materials are obtained by blending component polymers so as to achieve a set of properties desired by the customer and the supplier. Blending, therefore, is a common method of achieving the different grades of polymers to satisfy the requirements of different market segments. Often the polymers that are blended together have essentially the same chemical microstructures. Thus they are miscible with each other, and the final properties are simply an average of those of the constituents. The purpose of mixing different kinds of the same polymer is usually to create a specific "grade" that meets customer needs, such as processability and service performance. The mixing of these is typically done in the melt, usually with a compounding extruder. Similarly, the addition of small amounts of a polymer with a different chemical composition (or even just a different chemical microstructure) is usually accomplished by blending in the melt.
